Boiler Safety Valve Common Fault Analysis (Part 2)

2. Leakage at the Valve Body Joint Face

Leakage at the joint face between the upper and lower valve bodies compromises seal integrity and poses a safety risk. The primary causes and solutions are:

Cause 1: Insufficient or Uneven Bolt Preload

Uneven or inadequate tightening of bolts prevents uniform compression of the gasket.

Solution: Re-tighten the bolts following a crosswise sequence to ensure even gap distribution across the joint face. Using a gap measurement tool during tightening is recommended until proper torque is achieved.The main safety valve product names of China Safety Valve Network include:Wedge Single Disc Gate Valve,Stainless Steel Wire Port Gate Valve,Sprocket Wafer Knife-shaped Gate Valve,Sprocket Slurry ValveSCZ Series Flashboard Valve,Slab Gate ValveScum Flange Gate Valve,Stainless Steel Flange Gate Valve,Wafer Bevel Gear Knife-shaped Gate Valve,Z41H Manual Flange Cast Iron Gate Valve,ZT9928 Manual Slurry Knife-shaped Gate Valve,Z40/540/940H/Y Cast Steel Pressure Self-tight Gate Valve

Cause 2: Non-Compliant Serrated Gasket

Defects such as radial scratches, poor parallelism, overly sharp or worn serrations can lead to seal failure.

Solution: Implement strict quality control for spare parts and replace with a standard-compliant serrated gasket. Inspect the gasket before installation.

Cause 3: Poor Flatness or Foreign Debris on the Joint Face

An uneven mating surface or the presence of hard debris like weld spatter or sand impedes proper sealing.

Solution:

For Poor Flatness: Disassemble the valve and re-grind the joint face until flatness meets specifications.

For Foreign Debris: Thoroughly clean the joint faces during assembly to ensure no contaminants are present.

3. Main Safety Valve Failure to Actuate After Pilot Valve Operation (Main Valve Failure)

This critical failure, where the main safety valve does not lift upon pilot valve signal, poses a severe risk of overpressure damage. Mechanical binding is a primary cause:

Key Factor: Binding of Moving Components

This can result from improper assembly, contamination (dirt, debris), or component corrosion. Specific issues for piston-operated main valves include:

Inadequate surface finish of the piston chamber, including scratches, grooves, or hard spots, increasing friction.

Binding of moving pairs (e.g., valve stem and guide) due to debris or corrosion.

Solution: Complete disassembly and inspection of the main valve are required. Thoroughly clean and inspect all moving parts, removing contaminants and corrosion. Polish or repair surfaces such as the piston chamber and valve stem to ensure smoothness. Ensure proper alignment and apply suitable lubrication during reassembly.

Do you still need to know or purchase the following safety valve products: